Message-register circuits for machine-switching telephone-exchange systems.



C. L. GOODRUM.

MESSAGE REGISTER Gmculs Eo mAcmNE SwHcHlNG TELEPHONE EXCHANGE SYSTEMS.

APPLICATION FILED JUNE l5 |916.

Patented June 18, 1918. E

' 4 SHEETS--SHEET I.

/m/enor! 4 Char/es L bod/fam.

C. L. GOODRUM.

MESSAGE REGISTER CIRCUITS FOR MACHINE SWITCHING TELEPHONE EXCHANGE SYSTEMS.

APPLICATION FILED IuNE I5. 1916.

l ,269,702. Patented June 18, 1918.

4 SHEETS-SHEET 2.

Pfg. 2:

/n ven for: Char/e5 L. @ood/fum C. L. GOODRUM.v

MESSAGE REGISTER CIRCUITS FOR MACHINE SWITCHING TELEPHONE EXCHANGE SYSTEMS.

APPLICATION FILED TUNE l5. 1916.

/H V en for Char/e5 L, Good/fam. l

o@ M .W e s mm I d m M. 4 m I m I W Qn S Lm v HID MW .I w I .q M I AAM um m NLN. AWM mv w %\\\.;J M. \\m. WM, o l 7 L Y SMN NS 7,. 9 6 2 1 C. L. GOODRUM. MESSAGE REGISTER CIRCUITS roR MACHINE SwlTcRING TELEPHONE EXCHANGE SYSTEMS.

APPLICATION FILED JUNE I5. 1916.

Patented June 18, 1918.

4 SHEETS-SHEET 4.

/n Ven fof/.- Char/e5 l.. 6'00af/um unirsi) `strAtrEs 'PATENT OFFICE.

CHARLES I.. GOODRUM, OF NEW YORK, N. Y., ASSIGNOR TO WESTERN ELECTRIC COM- PANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

Speciiicaten Nof Letters Patent.

vPatented June 1s, 1918.

Application filed `Tune 15, 1916. Serial No. 103,855.

To all whom t may concern Be it known that I, CHARLES L. GooDBUM, a citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Message- Register Circuits for Machine-Switching Telephone-Exchange Systems, of which the' following is a full, clear, concise, and exact description.

This invention relates to telephone eX change systems employing machine switch` ing wherein a set of repeating relays is located before the first of a train of automatic switches, said relays being adapted to be operated by the sender to transmit impulses to the stepping magnets of 'such switches, talking current being fed both to the calling and called parties from relays of such set. In metering arrangements for machine switching telephone systems, the meter is usually actuated to count a call upon the operation of the called subscribers supervisory relay, which occurs when the called party removes his receiver. It is desirable that the meter of the calling party be notv actuated when certain numbers are called. Inasmuch,

however, as the called supervisory relay is located at the repeating relay set before the rst selector, and is therefore used in connections passing through any connector, this relay cannot discriminate between the calls.

The present invention provides for both kinds of service in a system of this character by segregating desired numbers on spe- `:ial groups of connectors and by employing controlling. devices operable in response to the called subscribers substation apparatus to discriminate between the classes of calls and to effect the` registration of desired classes of calls,

Referring to the drawings, Figure 1 shows the nder circuit; Fig. 2 shows the control circuit for the switches; Fig. 3 shows a group selector and an ordinary connector used when a number is called for which the calling partys meter is to be operated; and Fig. l shows a group selector and the s ecial connector which is used 'when a num r is called for which the calling partys meter is not to be operated.

It is thought that the invention will be most readily understood from a detailed description 'of the operations involved in setting up both kinds of connections. A connection involving a number for which the calling partys meter is operated will first be described.

Upon the removalv of the receiver at substation A, line relay 100 is energized over the following circuit: free pole of battery, left winding of relay 100, outer armature and back contact of cutoff relay 137, conductor 131, left winding of meter magnet 133, the telephonie apparatus at substation A, inner armature and back contact of relay 137, right winding of relay 100, to ground. Magnet 133 does not energize in this circuit.,

Relay 100, in attracting its right armature, closes the following circuit for a starting relay 101, common .to the group of lines to which sub-station A belongs: free pole of battery, relay 101, conductor 102, right armature and front contact of relay 100, conductor 103, conductor 104, left armature and back contact of slow relay 105,'to ground. Relay 101, in attracting its left armature, applies ground to the multiples 120 of the finders in which said line appears, and to the multiple commutator segments of the calling group in such finders. l This relay also closes a locking circuit for itself, independently of the left armature and back contact of relay 105, and in attracting its right armature, closes the following circuit to ini# tiate the primary movement of the line finder: ground, right armature and front contact of relay 101, slow relay 105, conductor 151, conductor 200, left karmature and backcontact of slow relay 201, conductor' 202, conductor 107, armatures and back contacts of release and escapement magnets RM,

A109, conductor 110, finder side-switch arm ai and its first contact, conductor 111, armature and back Contact of the primary magnet PM of the finder, winding of magnet PM, free pole of battery. Although relay 201 is in parallel with magnet PM in this circuit, it does not become suiiiciently magnetized to attract its armatures due to resistance 240. rI.`his 'magnet by making and breaking the clrcuit trace rotates the nder brush shaft 113, until the commutator brush 114 thereon engages the commutator multiple segment 115 of the calling group, which is now grounded at the left armature and front contact of relay 101, at which time a set of brushes 116, 117 and 118 on the iinder brush shaft 113 are in operative relation to the group of multiples containing those of the calling line 119, 120 and 121. The engagement of commutator hrush 114 with grounded commutator segment 115 closes a circuit for the escape magnet 109 to stop the nder. The magnet 109 is constructed to release the side switch upon its energization. The cir-` cuit for magnet 109 is as follows: free pole of battery, magnet PM, conductor 122, arm

and its first Contact, conductor 123, arm c and its first contact, escape magnet 109, oonductor 124, conductor 125, arm c and its first contact, conductors' 126, 127, commutator brush 114, commutator segment 115, conductor 128, right armature and front contact of relay 100, conductor 104, left armature and front contact of relay 101 to ground. The closure of the circuit just traced vfor the escapement magnet holds the primary magnet PM energized until the side-switch arms leave position 1, thus positively positioning the brush shaft and preventing overthrow. 1n position 2, the 'following circuit is closed for the secondary magnet SM, to step the positioned set of brushes 116, 117, 118 over the section containing multiples of the callingline 119, 120, 121: free pole of battery, magnet SM, its armature and back contact, conductor 130, arm d and its second contact, conductor 110, armatures and back contacts of escape and release magnets 109, RM, conductors 107, 202, left armature and 'back contact of relay 201, conductors 200, 151, relay 105, right armature and front contact of relay 101 to ground. When the brush 117 reaches the grounded terminal 120, the following circuit is closed to stop the nder: ground, left armature and front contact of relay 101, conductor 104, left armature and front contact of relay 100, conductors 131, 132, multiple 120, brush 117, conductor 134, arm o and its second Contact, conductors 135, 203, armature and back contact of relay 204, conductors 205, 124, escape magnet 109, arm e and its second contact, conductor 123, arm y and its second contact, conductor 136,1nagnet SM, free pole of battery. The escape magnet 109 energizes in this circuit, and the magnet SM remains energized. This circuit is opened as the side switch moves into position 3.

1n position 3, arm c closes the following circuit` to energize cut-oli' relay 137 of the calling line: arm c and its grounded third contact, conductor 126, brush 118, terminal 121, conductors 138, 139, cut-oil" relay 137, to free pole of battery. Relay 137, in operating, denergizes the line relay 100, which, in retracting its left armature, removes the calling condition 'from the multiples 120 of 'the 'calling line, and in retracting its right armature, opens the locking circuit of group haceros relay 101 and removes the calling condition :from the multiple commutator segments 115. 1n retracting its right armature, relay 101 denergizes slow relay 105. Before the right armature ot slow relay 105 closes its back contact, however, the calling supervisory relay 206 (Fig. 2) becomes energized over the calling line circuit as nder side-switch arms a, t, (Fig. 1) move into their third position. Relay 206, in attracting its inner armature, energizes a slow relay 207. This relay 207, in attracting its outer left armature, removes ground from conductor 208 before the right armature of relay 105 (Fig. 1) is fully retracted, thus preventing the closure of a circuit for the finder release magnet RM during this change-over operation.

In parallel with the circuit traced for the cut-oil' relay 137, a circuit Was closed for the right Winding of register magnet 133.

rl`his magnet is so Wound that it will not pull up unless current is flowing in both windings simultaneously in such a manner as to make the magnetizing effect cumulative. 1n position 3 of the finder side switch, the magnetic e'ect of the current oiv through the lei'tivinding of magnet 133 is neutralized by the current ilow through the right Winding.

1f during the secondary movement of the iinder brushes 116, 117, 118 over the multiples of the calling line group, multiples of a line engaged in conversation are encountered, the iinder brushes Will not stop on such multiples due to the opening of the circuit for escape magnet 109 by a relay 204 which responds when such lines are reached. Considering this feature more in detail, it Will be remembered that the circuit for energizing the escape magnet 109 to pass the side switch :from positions 2 to 3, led over the armature and back contact of relay 204. This relay 204 has its left winding in parallel With the secondary magnet SM, and as such magnet vibrates, making and breaking its own circuit and stepping the iinder shaft 113, the relay 204 vibrates synchronously therewith. As the nder brush 118 engages the multiple 121 of a line which is engaged in conversation, which multiple is grounded by the side-switch arm c and its third or fourth contact of another nder, or the sideswitch arm 9 and its third or fourth contact of a connector (Fig. 3), a circuit is closed to hold up relay 204 over its right Winding to maintain a break in the circuit of escape magnet 109 to prevent the same from energizing over a circuit including such busy line and the left Winding of relay 206 of the connecting circuit associated with such line. The said holding circuit for relay 204 is as follows: free pole of battery, right Winding of relay 204, conductor 209, conductor 140, arm c and its second contact, conductor 126, brush 118, to grounded multiple 121 of the busy line. Consequently, as

` the brush 118 engages multiples 121 of busy lines, the escape magnet 109 cannot energize to pass the side switch from position 2 to position 3, due to the fact that its circuit is opened at the armature and back contact of relay 204.

The inderhaving found the calling line A, the party th'ereat operates his sender S to transmit the first digit ofthe wanted number, which sender interrupts the line circuit in the well-known manner, causing the relay 206 to vibrate. Although the sender interrupts the circuit through the left winding cf register magnet 133, this magnet will not attract its armature since it is wound so as not to be energized by either winding alone. Relay 207 is slow and remains energized as the sender operates. This relay, in attracting its outer left armature, closes the following circuit for the release relay RR (Fig. 3) of the rst selector to interpose a break in the circuit of the release magnet RM thereof: ground, outer left armature and front contact of relay 207, conductors 210, right armature and back contact of relay 201, conductor 212, contact 213 of slow relay 214, conductor 215, conductors 302, 306, armature and back contact of magnet RM, relay RR, free pole of battery.

Upon the rst retraction of the outer armature of relay 206, the following circuit is closed for a slow relay 216,(which opens the connection of condensers 217, 218, with conductors 219, 220 to prevent the discharge. of such condensers from affecting the setting operation of the first selector (Fig. 3); ground, outer armature and back Contact of relay 206, conductor 221, right armature and front contact of slow relay 207, conductors 222, 223, slow relay 216, free pole of battery. Relay 216, in attracting its inner armature, grounds conductor 220, thus closing the following circuit for the escapement magnet 303 of the first selector (Fig. 3):

p ground, inner armature and front contactof relay 216, conductors 220, 304, first selector side-switch arm 2 and its first contact, conductors 305, 316, right Winding-of magnet' 303, to free pole yof battery. The escape magnet 303 is constructed to release the side switch from position to position upon its deenergization. Each time the inner armature of relay 206 is retracted, angimpulse is sent over the following circuit to the primary stepping magnet PM of the first selectorz' ground, inner armature and back contact of relay 206, conductor 224, inner left armature and front contactof relay 207, conductors 225, 219, 327, first selector side-switch arm 1 and its first contact, magnet PM to free pole of battery. Magnet PM imparts a primary movement to the first selector brush shaft (not shown) to `position a -set of described.

brushes 307, 308, 309 thereon in operative relation to the group of trunk multiples 310, 311, 312, terminating in connectors having access to the wanted line.

When the sender S restores and maintains ithe linecircuit closed, relay 206 remains energized, whereupon relay 216, after an interval, retracts its armatures. The retraction of the inner armature removes ground from the lower talking conductor 220, whereupon the escapemagnet 303 of the rst selector passes the side-switch arms to the second position, in which arm 4 connects the secondary magnet SM in circuit with an interrupter 313 to step the` positioned brushes 307, 308, 309 over the multiples 310, 311, 312 of the selected group of trunks.

If, when .ground is removed from the lower talking conductor by the denergization of relay 216, the interrupter 313 is on.

a metallic segment, the escape magnet 303 does not release due to the closure of the following circuit: free pole of battery, right and left windings of escape magnet 303 in series, armature and front contact of said magnet, conductor 314, arm 4 and its first contact, interrupter 313 to ground. When, however, the brushes of the interrupter 313 pass onto an insulated segment of the interrupter, the escape magnet becomes denergized, releasing the side-switch arms into position 2. This arrangement insures that the first impulse to the secondary magnet SM will be a full one.

In position 2, arm 3 energizesthe escape magnet over the following circuit: free poleV of battery, right winding of escape magnet 303, conductor 316, arm 3 and its second contact, secondary off-normal contact 317, normally closed, to ground. Contact 317 opens on the first secondary step of thel brush shaft. Busy trunks are those whose multi# 4 ples 312 are rounded, as will be hereinafter onsequently, as long as busy trunks are encountered, escape magnet 303 remains energized over its right winding and side-switch arm 3. When an ungrounded terminal 312 is reached, magnet 303-becomes inert, releasing the side switch .into

position 3. Arm 4 in movingpt its second contact, opens the circuit of the stepping magnet SM, thus stopping the brushes 307, 308, 309 upon the multiples 310, 311,312 of the seized trunk.

Arm 3, in moving into position 3, energizes release relay R2R2. over the following circuit to interpose a break in the circuit of connector release magnet R2M2: free pole of battery, relay R2R2, conductor 356, armature and back contact of magnet R2M2, conductor 357, terminal 312, brush 309, arm 3 and its third contact, conductor l302 to ground at the outer left armature and front contact of relay 207.

lThe calling party at substation A now operates his sender to transmit the tens digit of the wanted number. Upon the rst retraction of the outer armature ot relay 203, slow relay 216 energizes as before. llie following circuit is established for the primary armature and front contact of relay 207,-

conductors 225, 219, 327, selector side-switch arm 1 and its third contact, brush 307, terminal 310, conductors 380, 318, arm 5 and its first contact, conductor 329, left armature and back Contact 0f busy relay BR, conductors 331, 332, arm 10'and its irst contact, magnet P2B/I2, free pole of battery. ln parallel with the circuit just traced, a slow relay 333 is energized. This rela in attracting its armature, closes the iollowing circuit to energize the escapement magnet 334 of the connector: free pole of battery, magnet 334, armature and back contact of ringing cutoi relay RCC, conductor 336, arm 11 and its irst contact, spring 337 and armature of relay 333 to ground. The escape magnet 334 is arranged to release the side switch from position to position upon its denergization.

When the sender S restores and maintains the line circuit closed, relay 206, in holding its armatures attracted, causes the denergization of the slow relay 216, which in turn opens the circuit of relay 333 at the connector, which, in releasing its armature, opens the circuit of escape magnet 334, which, in denergizing, passes the connector side switch to position 2. Arm 10, in position 2, substitutes the secondary stepping magnet S22/I2 for the primary stepping magnet P2B/l2 in the stepping circuit.

The calling party new operates his sender S to transmit the units digit of the wanted number. Each time the relay 206 denergizes, an impulse is sent to the secondary stepping magnet S2M2 to step the connector brushes 320, 321, 322 into engagement with multiples 323, 324, 325 of the Wanted line. This circuit is the same as that traced for the primary magnet P2B/I2 up to the sideswitch arm 10, from whence it passes over the second contact of such arm, magnet 52E/.l2 to the free pole of 1cattery. As heitere, the slow relay 333 is energized in parallel with magnet S22/l2 while the impulses are lacing transmitted. When the sender S restores, relay 333 becomes denergized as before, opening the circuit of escape magnet 334, which, in denergizing, passes 'the sid'e switch to position 3.

1n position 3, the following circuit is closed to again energize slew rela 333 to prepare the ringing circuit: free po e orP laattery, relay 333, conductors 331, 332, arm

incarna 10 and its third contact, conductors 341, 342, arm 3 and its third contact to ground. Relay 333, in attracting its armatures, again energizes escape magnet 334, which, in attracting its armature,closes the ringing circuit as follows: tree pole ot generator 340, ringing cuto relay RUG, armature and front contact of magnet 334, conductor 343, arm8 and its third contact, brush 321, terminal 324, conductor 344, bell 345, condenser 346, conductor 347, terminal 323, brush 320, arm 7 and' its third contact, conductors 348, 342, arm 6 and its third contact to ground.

`When the called party, in responding, removes his receiver, ringing cut-oi relay RC() operates, opening the circuit of escapement magnet 334 which passes the side switch into position 4. Relay 333, being slow to release, holds its armature attracted for an instant after side-switch arm 11 reachesits fourth position. An impulse is thus transmitted over the following circuit to operate the called supervisory relay 228, which is adapted to transfer the control of the release of the irst selector and connector lescape magnet 109 to cause the reversal of the direction of current dow in the calling linevto register the call; ground, armature and spring 337 of relay 333, arm 11 and its fourth contact, conductors 349, 350,l terminal 311, brush 308, arm 2 and its third contact, conductors 304, 220, inner armature and baci: contact of relay 216, conductor 229,left winding of relay 228 to free pole of loattery. Relay 228, in attracting its rightarmature, energizes a slow relay 214. Relay 214, in attracting its right armature, opens the connection of ground from the outer left armature and iront contact of relay 207 to conductor 215, and substitutes thereior ground over said right armature, and since the relay 214 is now controlled by the called party, the release et the selector and conhector is dependent upon the replacement or the receiver hy the called party.

Relay 228, in attracting its left armature, closes the :following circuit for the escapement magnet 109 of the iinder side switch to energize the same to pass the side switch from position 3 to position 4: ound, left armature and front contact o' relay 228,

` conductors 230, 205, 124, magnet 109, arm c winding, thus removing it from the talln'ng circuit. Arm c, in position 4 of the finder side switch, maintains the cut-oil' relay 137 and magnet 133 energized.

When the calling party restores his lreceiver, relay 206 becomes denergized, and in retracting itsinner armature, opens the circuit of relay 207, which, after an interval, retracts its armature. The retraction of the outer left armature of this .relay closes the circuit of release magnet RM of the finder as follows: ground, outer armature and back contact of relay 207, conductor 208, conductor 150, right armature and back contact of slow relay 105, primary off-normal contact- 152, conductor 153, release magnet RM, to free pole of battery.

When the called party replaces his receiver, relay 228 becomes denergized, and, in retracting its right armature, opens the circuit of slow relay 214. This relay, after an interval. retracts its armatures. The retraction of the right armature removes ground from conductor 215, which has been maintaining energized the release relays RR and lft'R2 of the selector and connector, respectively, whereupon these relays retract their armaturesl and close the circuits of the associated release magnets RM, RZMZ, respectively. These magnets RM and Rall/I2, in operating, restore the side switches in the well-known manner, and when the olf-normal contacts 371, 372 open as the shafts reach their normal positions, such magnets are denergized.

The operations involved in tracing a charged call having been described, the operation of the system in calling a free number will now be described, referring to Figs. 1, 2 and 4. y

It will be noted that Fig. 4 is similar to Fig. 3, except that the conductor 349,con-

nected between the fourth contact of the connector side-switch arm 11 and conductor 350 is omitted, and a relay 360 and a pair of condensers361, 362 are added. The talking battery for the called substation Bis fed over the windings of this relay 360 instead of from the relay 228, (Fig. 2) -of the repeating relay set as in the case of a charged call. The free numbers are segregated upon connectors of the type shown in Fig. 4, and in calling a free number, the operation of the system is the same as that described in calling a charged number up to the point when the called party responds by removing his receiver from the switch hook at substation B. It will be remembered that in the circuit arrangement of Fig. 3 the slow relay 333 is energized at this time over thel following circuit: free pole of battery, slow relay 333, conductors 331, 332, arm 10 and its third contact, conductors 341, 342, arm 6 and its third contact to ground, and that this slow prim ary relay in holding its armature attracted for an interval after side-switch arm 11 reaches its fourth contact, transmits an impulse (Figs. 3 and 2) to relay 228, which, in operating, energizes the escapement magnet 109 of the iinder to pass the finder side switch to position 4 to reverse the -direction of current flow in the calling line to cause the meter magnet 133 to operate. In the special connectors shown in Fig. 4, conductor 349 is omitted. This impulse is therefore not passed to the relay 228 and the direction of current How in the calling line is not reversed, since the side switch of the finder stays in the third position. Position 3, in such event, is the talking position of the finder side switch instead of position 4. The circuit for feeding battery to the calling party then leads as follows: free pole of battery, right winding of relay 206 (Fig. 2) conductors 233, 143, arm b and its third contact, conductor 134, brush 117, terminal 120, conductor 132, left winding of register magnet 133, through the telephonie apparatus at substation A, conductor 146, terminal 119, brush 116, conductor 147, arm a and its third contact, conductor 144, conductors 234, 235, left winding of relay 206 to ground. Talking current is fed to the called party over the following circuit (Fig. 4): free pole of battery, left winding of relay 360, conductors 366, 367, arm 8 and its fourth contact, brush 321, terminal 324, conductor 344, telephonie apparatus at substation B, conductor 347, terminal 323, brush 320, arm 7 and its fourth contact, conductors 368, 369, right winding of relay 360 to ground. Condensers 361, 362, (Fig. 4) and 217, 218, (Fig. 2), conductively separate the calling and called ends of the connecting circuit, and indue-tively unite the same.

When the calling party restores his receiver upon the termination of the conversation, relay 206 becomes denergized, and, in retracting its inner armature, opens the cirv cuit of relay 207, which, after an interval, retracts its armatures. The retraction of the outer left armature of this relay closesk the circuit for release magnet RM of the nder as previously traced. The retraction 1,15 of the outer left armature of relay 207 removes ground from the third or test conductor 302 (Fig. 3) which denergizes release relays RR and R2R2 of the selector and connector, respectively/, which, in falling back, close the circuits of release magnets RM and R2M2, respectively, of such switches, whereupon the same are released.

Referring back to that point in the operation where the finder side switch goes -into position 3, u on the finding of the line, arm d of the nder side switch in this position extends the in-starter wire 155 to the out-starter wire 156 leading to the next idle finder. If, now, the ill-starter Wire is grounded by reason of the initiation of a call, and the finder restores, arm d, in moving back to its first contact, would disrupt the starting circuit operating such idle finder. ln order to prevent this, a slow relay 201 is provided, which relay is energized when relay 211i operates upon the respouse of the called party. lt, now, conductcr 151 is grounded, by reason of the initiation ot a call in the group to whichl position 1 by the release of the finder when the calling party hangs up, it will not disrupt the starting circuit, When the starting ground is removed from conductor 151,

relay 201 falls back, provided relay 21a is 25 denergized.

The right amature and associated con` tact of slow relay 201 comes into play when the called party is the rst to hang up his receiver upon the termination of the conversation. Considered more in detail, the replacement ofthe receiver by thc called party denergized relay 228, which, in releasing its right armature, denergized slow relay 214. Although relay 207 is at this time energized, and at its outer left armature is maintaining ground upon conductor 210, this ground is not transmitted to conductor 212, since relay 201, bein slow, holds its right armature attracted or an interval after its circuit is opened by the retraction of the left armature of slow relay 214. Thus there is a sucient interval between the retraction oi the right armature of relay 214 and the retraction of the right armature of relay 201 for release relays RR, R21?? of the selector and connector, respectively, to denergize and restore such switches.

ln case the called line is busy, the test multiples 325 thereof are grounded over arm 9 and its third or fourth contact of the connector connected to such line, or over the finder side-switch arm c and the third or fourth contact thereof, dependent upon whether the line isbusy as a called or a c3 calling line. In such event, the busy relay BR energizes from the ground-on such test multiples, and locks up, preventing the side switch from going into the ringing position, and appliesl a busy signal to the calling line B0 from a busy tone apparatus 373. Consid-1 ered more in detail, 1t will be remembered that slow relay 333 is energized in parallel with the secondary stepping magnet S2M2v when the sender is transmitting the units digit of the wanted number. This relay is assegna provided with a spring 337 which is adapted to engage contact 375 before breakingcontact with the armature of such relay. Consequently, if ground is present upon the test multiples 3.25 of the selected line, the follow- 7u ing circuit is closed to hold the escape magnet 334 in position 2 free pole of battery, escape magnet 334, armature and back contact of ringing cut-oli' relay BCG, conductor 336, arm 11 and its second contact, spring 75 337, contact 375, conductor 376, busy relay Bit, spring 377 thereof, contact 378, conducto-r 379, arm 9 and its second contact, brush 322, grounded test multiple 325. Re lay BR, in attracting its right armature, 8o locks itself to ground over side-switch arm 6, and in attracting its left armature connects the busy tone apparatus 373 over sideswitch arm 5 and its second contact to the upper talking conductor 380, and thence to the calling line. The release of the switches takes place upon the replacement of the receiver by the calling party, as hereinbeforc described.

What is claimed is:

1. In a telephone exchange system, the combination with telephone lines of different classes, senders therein, message registers associated therewith, selector switches, two groups of .connector switches, and nder switches for connecting said lines to the selector switches, said lines being grouped as called liines on said connectors according to the class to which they belong, control circuits adapted to coperate in the setting of said switches by said senders, a relay associated with each control circuit and with each of the connectors of one group, means for operating either the relay in the control circuit or the relay in the connector upon the response of the called party, dependent upon the character of the called line, and means including the finder switch operated when the control circuit relay is operated to actua-te the callin line message register.

2. 1n a telep one exchange system, the combination with telephone lines of dierent classes, senders therein, connecting circuits including selector and connector switches, said connector switches being divided into two 'rcups and the lines being grouped as called lines therein according to the class to which they belong, non-numerical switches for associating said lines with said connecting circuits, a message register magnet for 12@ each line having two windings, one included in the line circuit and the other in the test wire of said non -numerical switch, said windings being differential when said line is extended to a connecting circuit, control circuits adapted to coperate in the'setting of said switches by said senders, a relay associated with each control circuit and with each of the connectors of one group, `means for operating either the relay in the control circuit or the relay in the connector upon the response of the called party, dependent upon the character of the called line, and means permanently associated with the non-numerical switch actuated by the operation of said control circuit relay for reversing the flow of current in the calling line to operate said register.

3. In a telephone exchange system, the combination with telephone lines of diierent classes, connecting circuits including a selector and connector switches, said connector switches being `divided into tW 0 groups and the lines being grouped as called lines therein according to the class to which they belong, senders, finders for associating said lines with said connecting circuits, side switches for controlling said Enders, a message register magnet for each line having two windings, one included in the line circuit and the other in the test wire of said finder, said windings being differential when said line is extended to a connecting circuit by a linder, control circuits adapted to cooperatein the setting of said switches by said senders, a relay associated with each control circuit and with each of the connectors of one group, means for operating either the relay in the control circu1t or the relay in the connector upon the response of the called party, dependent upon the character of the called line, and means for advancing the inder side switch upon the operation of said control circuit relay to reverse the di- 'rection of current flow in the calling line to operate the message register.

4. In a telephone exchange system, the combination with telephone lines of different classes, message registers therefor, selector switches and two groups of connector switches, said lines being grouped as called lines on said connectors according to the class to which they belong, senders, nders having side switches for associating the lines with said switches, control circuits adapted to coperate in the setting of said switches by said senders, a relay associated with each control circuit and with each connector of one group of connectors, means for operat- 'ing either the relay in the control circuit or the relay in the connector upon the response of the called party, dependent upon the character of the called line, and means including the side switch of the finder operated when the control circuit relay is operated to actuate the calling line message register.

5. In a telephone exchange system, the combination with telephone lines of different classes, senders therein, message registers associated therewith, selector switches and two groups of connector switches, finders having side switches adapted to associate the lines with said switches, said lines being grouped as called lines on said connectors according to the class to which they belong, control circuits adapted-to coperate in the setting of said switches by said senders, a relay associated with each control circuit and with each of the connectors of one group, means for operating either the relay in the control circuit or the relay in the connector upon the response of the called party, dependent upon the character of the called line, and means controlled by the operation of the finder side switch for actuating the calling line register dependent upon the relay operated.

6. In a telephone system, a calling line, connecting circuits,l an automatic switch for extending said line to one of said connecting circuits, called lines of dii'erent classes, selectively operable switches for extending a connecting circuit to a called line, a particu,- lar class of called lines'being segregated at a particular selective switch, means for operating said selective switches, means to release said selective switches, said release means being under the control of the calling line while the selective switches are being operated, a message register associated with the calling line, a controlling device associated with each of said connecting circuits effective when a called party answers to operate said register and to place said release means under the control of the called line,

vsaid controlling device further serving to feed battery current to the called line, and means associated with said articular selective switch which may be su stituted for the controlling device to supply current to a nector switch, a plurality of connecting circuits terminating in said switches, means for extending calling lines to said connecting circuits, a group of repeating relays adapted to transmit impulses directly to the operating magnets of said switches, one of the relays being effective both in the establishment of a telephone connection and in its registration, and a controlling device associated with each of the particular connector switches and which may be substituted for said last. mentioned 'relay in the establish ment of a call which is ineffective in call registration.

8. In a telephone system, a calling line, a connecting circuit, selectively operable switches, anvautomatic switch for connecting the callingline to said connecting circuit, an auxiliary switch for controlling the operation of the automatic switch, called lines of different classes, a particular class of said lines being segregated at a particular selective switch, means for actuating the selective switches to extend said connecting les circuit to any one of the celled lines, release mea-ns for seid switches, seid Vrelease means being unei the control of the calling line while a connection is being extendedg e message register asseeieed with the ceiling line, Said 'egister esponsive to the actuetion of the auxiliar-Ty switch, e line relay im seid connecting cicuit foi supplying tellsing Current te e called linee mesme eentielled by e celle line for operating said relay te eetuee said auxiliary, swieh and te Temeve the control of seid; release means. from' the calling te the celled line, and e line relay associated with Seid periculai switch which may be substituted fer seid 5125i, relay te supply talking current when e eonneetimi ie extended te e line of seid particule? class of linee.

)ln witness whereof, l hereunte subscribe my neme this llfLl-i dey of June, A. D; 191.6.

CHARLES L., GDRUi/, 

